Conventional electric vehicle battery trays must support a plurality of batteries, which cumulatively can weigh as much as 1,700 pounds. As a result of such load bearing requirements, battery trays tend to be of a stamped metal construction. Such battery tray constructions, however, have the problem of adding weight to the vehicle as well being susceptible to corrosion.
Attempts have been made to design a polymer based battery tray to take advantage of the light weight and corrosion resistant qualities of certain plastics. Injection molding is one method that may be used to manufacture such a tray. Such a molding technique, however, requires a draft angle of 4 to 7 degrees in order to remove the tray from the core of the tool. This results in the upper wall of the tray extending a substantial distance outward of the battery pack. Any such distance is a liability to an automotive designer that has limited packaging space.
A problem associated with both metal and polymer constructed battery trays is how the trays may be employed to assist in maximizing battery life. One variable that directly impacts battery life is the thermal conductivity of the tray. Controlling the thermal conductivity of the battery pack via the battery tray enhances battery pack life.
What is desired, therefore, is a polymeric battery tray sufficiently strong to house an electric vehicle battery pack while minimizing packaging space and maximizing thermal conductivity control.